BAPAlmirante Grau(CLM-81) is a De Zeven Provinciën-classcruiser in service with the Peruvian Navy. Completed for the Royal Netherlands Navy in 1953 as HNLMS De Ruyter (C801), she was acquired by Peru in 1973. Since then, she has served as the fleet flagship of the Peruvian Navy. Almirante Grau underwent a major modernization program between 1985 and 1988 during which she was fitted with new weapons and electronics. She is currently the last gun cruiser in service in any navy.

From 1985 until 1988, she underwent a major modernization program by Amsterdam Naval Services (ANS) at its shipyard in Amsterdam, period during which she was denominated Proyecto de Modernización 01 (Modernization Project 01) or PM-01. Her role as flagship was assumed by her sistership Aguirre as Almirante Grau. Both ships regained their former names when the ex-De Ruyter reached Callao on 15 February 1988.

The upgrade program carried out in the Netherlands included the following: